79 



MuRCHisoNiA Hespelerensis, Whiteaves. 



Murchisonia Hespelerensis, Whiteaves. 1884. This volume, pt. 1, p. 24, pi. 41, 



fig. 3. 



Hespeler, T. C. Weston, 1867, one perfect cast of the interior of the 

 shell; Township of Glenelg, J. Townsend, 1883, a similar specimen. 

 This species should, perhaps, be referred to Pleurotomaria rather than to 

 Murchisonia. 



Murchisonia Mylitta, Billings. 



Murchisonia Mylitta, Billings. 1862. Geol. Surv. Canada, Pal. Foss., vol. I, 



p. 157, fig. 140. 



Elora, R. Bell, -1861 : a single oast of the interior of the shell with a 

 small portion of the test preserved. The specimen is represented as 

 measuring twenty-four millimetres, or a little less than an inch in height, 

 but the figure of it is slightly restored, the spire of the original being 

 rather badly preserved and its apex broken off. According to Mr. Bill- 

 ings, the shell of this species is short and consists of " four or five ventri- 

 cose whorls, with a narrow spiral band a little above the middle on the 

 last,'' and, it may be added, on the last only. 



Murchisonia. (Species uncertain.) 



Plate 12, fig. 3. 



Between the years 1878 and 1882 Mr. Townsend collected, at Durham, 

 five specimens of a rather large short-spired Murchisonia which may 

 represent the adult condition of M. Mylitta, but which in some respects 

 seems to be intermediate in its characters between that species and M. 

 Xanthijype, Billings. The largest of these specimens, which is imperfect 

 at the apical end, is fifty-four millimetres or upwards of two inches in 

 height or length, and three of the smaller ones have most of the test pre- 

 served. In these latter the slit band, which is enclosed in a prominent 

 but narrow spiral ridge or keel, encircles the outer volution above the 

 mid-height, especially near the aperture,vas represented by the figure on 

 Plate 12, and the volutions of the spire are angulated a little below the 

 mid-height. The whole five give one the impression of a shell like the 

 Murchisonia hicincta of Hall, with only one spiral keel developed, and 

 closely resembling that form of M. hicincta from Ardre figured by Lind- 

 strom under the name Pleurotomaria hicincta on Plate 8, figure 20, of the 

 " Silurian Gastropoda and Pteropoda of Gotland." In that monograph 

 the " Trochonema ( Eunema) fatua of Hall, from the Niagara limestone of 

 Wisconsin, is regarded as a synonym of Pleurotomaria hicincta. 



